Suspended tile ceilings have been used extensively in industrial, office and home building construction. Suspended ceilings are particularly useful in areas where it is not desirable to close off the space between the ceiling level and the floor above. This provides access to wiring, heating, plumbing and other service installations. Over an extended period of time, acoustical ceiling tile normally become soiled, particularly in industrial areas, commercial cooking establishments and offices. In addition, air conditioning outlets, particularly those extending through the suspended ceiling, distribute a considerable amount of soot over the panel surfaces.
It is very difficult to clean acoustical tiles. Normally acoustical tiles have holes extending through the face and into the acoustical layer behind the face. Should one attempt to wash the acoustical tile, the wash water passes up through the holes into the water absorptive acoustical backing and leaches dirt back to the face of the tile. This can result in spotting of the tiles after they have been washed. People have attempted to paint the tile face instead of washing. However, this normally plugs the holes of the acoustical tile reducing its acoustical properties. Attempts have also been made to bleach the suspended ceiling tile to bring it back to its natural white color. However the bleach, if not properly applied, can be corrosive to the suspending T-bar members and can discolor the suspended ceiling tile. A system has been developed which successfully paints the ceiling tile without clogging the acoustical holes. The paint is a highly loaded titanium dioxide base. However, in spraying this paint onto the tile, it is necessary to cover all of the suspended T-bars with tape to prevent overcoating the metal. This becomes a very time consuming and labour intensive job.
Attempts have been made in providing vinyl coated acoustical tile. However because of the holes provided through the vinyl, wash water can leach dirt from the acoustical padding of the tile back through the porous vinyl coating onto the surface and thereby discoloring the washed panel face. An example of this type of tile is disclosed in U.S. Pat. No. 4,040,213 which consists of an acoustical prefabricated panel having a thin flexible laminated facing adhesively secured to the fiberglass acoustical panel. To provide for sound absorption, holes are provided through the thin flexible laminated facing to expose the sound absorption fiberglass panels. The thin flexible laminated facing is made up of laminate layers of thin, impact resistant, metallic film laminated to glass fiber scrim which is, in turn, laminated to a synthetic film. If no holes were provided in the face of this panel, the panel would be washable. However, its acoustical properties would be very poor, thereby necessitating the acoustical pattern of holes and in turn precluding washing. A further example of this type of acoustical suspended ceiling tile is disclosed in U.S. Pat. No. 4,487,793. The acoustical tile includes a base structure of fibrous material with another face of vinyl material. A plurality of apertures are provided in the outer vinyl layer. Such relationship provides for satisfactory acoustical noise reduction properties, however, when any attempts are made to wash the panel, the wash water passes through the apertures in the outer vinyl coating and leaching dirt back down to the face of the panel. Such leaching action may occur over a number of hours or days making it impossible to properly clean the face of the acoustical panel.
Examples of suspended ceiling tiles, which have washable metal faces, are disclosed in U.S. Pat. Nos. 1,972,563 and 3,695,395. The difficulty with each of these panel arrangements is that wash water can pass through the apertures in the metal panel mixing with dirt on the inside of the metal panel and, eventually by capillary attraction, reappearing on the face of the panel after it is wiped down to resoil the panel face.
Plastic panels, which provide washability of the face of the panels, are disclosed in U.S. Pat. No. 2,966,954. The panel is a composite of two or more plastics which include apertures offset from one another to define a tortuous path and thereby provide sound deadening properties. The difficulty with this system is that wash water used in cleaning the face of the panel can flow to within the several spaces between the panel portions and eventually run back resulting in resoiling of the panel face even after the washed panels have been wiped down.
Suspended ceiling panels, which include a continuous washable surface, are disclosed in U.S. Pat. Nos. 4,241,806 and 4,248,647. In U.S. Pat. No. 4,241,806, a panel construction consists of an outer decorative layer of plastic which is very light and thin. Underlying the decorative plastic layer is a perforated steel plate which is also relatively thin. The perforated steel plate transmits sound waves which pass through the outer decorative film into an acoustic absorption layer. Due to the outer layer being continuous, it is possible to wash down the panel without causing any soil behind the perforated metal plate leaching out onto the outer surface of the panel.
U.S. Pat. No. 4,248,647 discloses an acoustical suspended ceiling tile which has a washable, distortion-free, decorative plastic film on the front face of the panel, such decorative film may be of Mylar polyester films (trade mark). The tile has a frame which defines a recessed area providing an acoustical base portion. The plastic film is adhered to the frame and heat-shrunk to provide a taut distortion-free film across the face of the panel. Such panels are not practical for most types of suspended ceilings because the film can be readily punctured, due to it being spaced from the recessed acoustical base, thereby ruining the appearance of the panel.
Other types of suspended ceiling tiles which include an outer plastic film or metal foil to provide for washability of the tiles are disclosed in U.S. Pat. Nos. 3,204,380 and 3,771,213. Plastic film as disclosed in U.S. Pat. No. 3,204,380 is applied to the face of each interlocking acoustical tile. The film is drawn tightly to the face of the tile by the use of vacuum or the like, and with heating the softened film edges are secured by adhesive to the tile edges. The plastic sheet overlying the tile face acts as a vibrating member to transmit the sound waves to the underlying base which absorbs the sound energy sufficiently to appreciably reduce noise. The plastic film face is washfast and water impervious, to provide tiles which can be cleaned or washed without damage to the ceiling or other surface to which the tiles are applied, and without impairment of their acoustical properties. In U.S. Pat. No. 3,771,213 a metal foil is applied to the face of the tile. To ensure that the metal foil tightly fits the face of the tile and preventing sagging in the centre portion of the tile face, mechanical embossing of the foil is used to draw the foil tightly between the edges of the tile. Sound waves will strike against the foil and cause the foil to vibrate, whereby the sound is transmitted to the punched fibre-board backing where the sound vibrations are absorbed within the holes of the fibre-board backing of the suspending ceiling tile. However, both of these tile systems are not useful in a practical sense because the plastic film or metal foil can be readily punctured due to normal wear and tear in an office, industrial or home environment, hence rendering it impossible to clean the tile face. Furthermore, with the stretching or tightly fitting of the plastic film or metal foil to the face of the acoustic panel, the face can reflect by vibration more sound than it transmits through to the fibrous sound-absorbing backing material, hence requiring the use of holes or the like in the outer facing, thereby suffering from the drawbacks of the aforementioned U.S. Pat. No. 4,040,213.
In view of these difficulties with the existing expensive constructions which do offer washability of the panel for purposes of refurbishing, in most installations the acoustical ceiling tiles are simply replaced with new tiles, rather than any attempt made to refurbish the existing tiles with more expensive washable type.
According to this invention, a system is provided for refurbishing an existing suspended ceiling tile without the need to replace the existing tile and, in turn, provide a system which is washable and can enhance the acoustical properties of the tile ceiling.